Process of impregnating thick textile fabrics with gum



Jan. 31, 1950 J. coLMANT 2,495,808

PROCESS 0F IMPREGNATING THICK TEXTILE FABRICS WITH GUM Filed July 19, 1947 C Zhu/enfer Jew/v hamm/7 a), i i.

y /fpenfs' Patented im. a1, 195o PROCESS F IMPBEGNATING THICKA TEXTILE FABRICS WITH GUM Jean Colmant, Tournai, Belgium, assignor to Etablissements Colmant & Cuvelier Societe Anonyme, Tournai, Belgium, a Belgian com- Dany Application July 19, 1947, Serial No. 762,085

In Belgium March 29, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires March 29, 1961 4 Claims. (Cl. 154-52) The present invention relates to the impregnation of thick textile fabrics, especially of multiple-ply fabrics, with gum. -Generally it is difficult to obtain a complete and homogeneous impregnation of these fabrics, even if acting under pressure, because the gum in a fluid state, for instance such as latex, cannot penetrate abundantly, in a homogeneous manner, with the charges which have been incorporated therein, into all interstices of the inner plies if the latter. are of tight fabric. Now, it is necessary to use tight cloths in all cases where the fabrics must have a great resistance against mechanical stresses as well as against wear. This is especially the case for rubberised belts.

The present invention has for its object to n realise a thorough and homogeneously distributed penetration of the gum into the plies of the fabric, under such conditions as to cause the gum to contribute to uniting the plies to vthe fabric removable and uniformly distributed cores which penetrate deeply into the fabric, preferably from side to side of the same, whereafter these cores are removed and the impregnation with gum is performed. Through the hollows left by the departure of the cores the gum has an immediate and direct access to all the plies and assures an abundant impregnation and an intimate coating of all the fibres.

The introduction of the cores may be performed in any suitable way, either during or after the weaving. In order to cause the hollows, left by the cores to remain widely opened for receiving the gum, it will generally be advantageous to x the fabric by means of a dressing or size before the removal of the cores, to prevent shifting of the bres of the fabric and closing up of the hollows.

According to an advantageous method of carrying out the new process the cores are introduced, during the weaving, in the form of binding threads, which are woven in such a manner as to permit their easy removal from the fabric.

The process according to the present invention offers the possibility of using, in conveying and in driving belts, plies of rectilinear threads, such as those known under the name of cord fabric. vIn these fabrics, which are employed particularly in the manufacture of tyre casings, the warp threads are not interwoven with other threads, but are united with each other by simple gumming. They are not subjected, as in other fabrics, to the fatigue which is due to the friction of the weft threads Yunder the actionof repeated stress applied to the fabric, and due to this fact they work under the most favorable conditions with respect to their resistance. However, up to the present, these fabrics were not suit-able for the manufacture of flat and broad belts, because the simple gumming is not sufcient for withstanding the shearing stresses which arise between the parallel threads, these stresses causing the rapid destruction of the belt. If, instead of uniting the parallel threads by ordinary gumming, a deep impregnation according to the present invention is applied to the plies of longitudinal rectilinear threads in alternate relation to plies of transverse rectilinear threads, there is obtained an impregnated multiple-ply fabric which is penetrated through and through by a multiplicity of little gum pillars which firmly unite all the plies and all the threads and resist to the shearing stresses. Moreover, the transverse threads embedded in the gum afford the necessary support to the fasteners used to join the ends of the belt.

The invention will be easily understood with reference to the accompanying drawing which shows, by way of example, some forms of execution thereof.

Figure 1 shows a diagrammatic section, on a somewhat enlarged scale, through a four-ply fabric with binding threads woven so as to form cores.

Figure 2 shows a section through the same fabric after removal of the cores and impregnation with gum.

Figure 3 is a perspective view, on an enlarged scale, the superposed plies of rectilinear threads.

Figure 4 shows the position of a binding thread.

Figure 5 shows a section. in two different planes through the fabric after impregnation.

Figures 6, 7 and 8 show other arrangements of the plies of superposed threads'.

The fabric shown in the drawing comprises four plies the warp threads of which are designated by a, the weft threads by b and the binding threads by c. If the binding threads are woven, as shown, in such a manner that, as they extend across the fabric, they form loops which leave all the weft threads on the same side. it will be possible to withdraw all the binding threads from the fabric without affecting its constitution. Before the binding threads are withdrawn, the fabric is treated with a very diluted latex acting as a size or dressing. By virtue of its dilution this latex penetrates easily the fabric and fixes the fibres of the same without obstructing the interstices which will serve as ducts for the subsequent nal impregnation. When, after drying, the threads c which with their loops formed cores in the fabric, are with- `rawn, the latter has the aspect of a thick screen the holes of which are widely open through and through.

Thereafter the nal impregnation is performed by way of immersion into one or several latex baths of higher concentration. 'I'he gum penetrates abundantly and thoroughly into all the hollows and enters therethrough into the intimate texture of the fabric around every fibrev which is thereby impregnated and coated. At this state the fabric is traversed through and through by a multitude of small rubber pillars d.

After complete drying the fabric is vulcanised, with or without an outer coating of rubber. If there is provided agum coating, this unites with the gum pillars which fill the hollow of the fabric, the coating being thus positively riveted to the fabric.

It is to be noted that the space occupied in the fabric by the gum pillars d is not established at the expense of the closeness of the warp threads and that consequently no reduction of the tensile strength will result therefrom. In fact. in the absence of these pillars said space would be occupied by the binding threads which are always used in fabrics of this kind, to assure the cohesion of the same. The binding by threads is substituted, in the process according to the present invention, by binding by means of small pillars or rivets of gum, such binding not only being more eilicient but imparting to the fabric greater flexibility and elasticity.

' Instead of being woven in a manner aording the possibility of an easy removal, the binding threads may be made of a soluble material, for instance of cellulose acetate, and they may be woven in any way whatever. In this case the binding threads are removed by dissolution in a suitable solvent and, after drying, the impregnation with gum is performed. whereby the spaces left by the dissolved threads are filled up.

Figures 3 to 8 show the application of the invention to a fabric produced by the simple superposition of plies composed of parallel threads.

In Figures 3 to 5, a, a designate the warp threads and b, b, the weft threads, the threads preferably running at right angles to each other.

The binding threads c are woven between thev warp and the weft threads in such a manner as to ll up the spaces which separate these threads and to form loops adapted to be'easily withdrawn when a traction is imparted to the ends of the threads c for removing the same.

After having eventually sized the fabric such as shown in Figure 4, with a dressing, the threads c are withdrawn and the fabric is immersed into a gum bath for obtaining the structure shown in Figure 5, wherein the holes between the threads a and b are lled by small gum pillars d from which start in all directions ramifications which fill up all the spaces and envelop the threads a and b.

The impregnated fabric obtained in this manner is particularly suitable for the manufacture of driving belts and of carrying belts which are subjected to great stresses, because the rectilinear warp threads work under the most favorable 4 conditions, without being subjected to wear by the friction of weft threads.

Forthisreasonitisalsopossibletouse threads of a large cross-section and threads twisted to cords, whereas in the case of fabrics made from interwoven threads the section of the threads is limited by the fatigue to which the threads are subjected and which increases proportionally to the section.

The invention also gives the possibility of using wire, either bare or covered, instead of some of the warp threads, at intervals, or of all the warp threads, or again of the weft threads, the execution of the impregnation process not being modilied in any respect.

YFor giving the product a better finish, a few line warp threads a (Figure 6) may be woven in the upper and lower plies of the weft, but without these supplemental threads intervening in the actual constitution of the fabric or contributing to its resistance.

Figures 7 and 8 show other arrangements in the structure of the threads, that according to Figure 'l adding a ply of warp threads to the upper face for increasing the strength of the warp with respect to the weft, while in that according to Figure 8 the relative strength of the weft is reduced by the wider spacing of the weft threads and by' their alternation from one ply to the other, for the purpose of giving to the whole structure a greater flexibility in the longitudinal direction, the lower ply being tighter. to permit the hooking in of the fastening threads. Ob

viously other arrangements may be provided.

In the different cases describedabove and i1- lustrated in the drawings there is obtained. after the impregnation, a fabric which oers the following advantages:

The impregnation with gum is much deeper and more abundant than that obtained with the usual processes, so that the bres of the fabric are completely embedded in the gum. As it has not been ltered by the whole thickness of the fabric, the gum is homogeneous at every point, with all of its charges.

The multiplicity of small gum pillars which pass through the fabric from side to side, firmly unite all the plies and the bres of the fabric in the sense of the thickness of the latter, in like manner as would be done by rivets or by ligatures, but with greater flexibility and strength.

To this last advantage, which is very important for rubberised belts, there is to be added the fact that a belt which has been impregnated according to the present invention is particularly suited to receive an outer coating of gum, the small rubber pillars, which unite themselves with said coating, forming as many roots which are deeply anchored in the fabric, so that it is impossible to tear off the one from the other.

The invention covers not only the process of impregnation described above but also the products and articles impregnated according to this process, irrespective of the method of introduction and of removal of the cores, before impregnation, as well as the arrangement and the distribution of the cores.

I claim:

1. In a process of preparing thick textile fabrics impregnated with gum, introducing into the fabric during the 4weaving thereof threads forming removable cores from side to side of said fabric, withdrawing said threads from the fabric thereby leaving recesses in said fabric, then impregnating said fabric with gum and causing the gum to have access through said-recesses to the interstices between the fibres of said fabric.

2. In a process of preparing thick textile fabrics impregnated with gum, introducing into the fabric during the weaving thereof looped threads forming removable cores from side to side of said fabric, treating the fabric with a dressing agent to fix the bres in their relative positions, withdrawing said threads from the fabric thereby leaving holes extending through said fabric, then impregnating the fabric with gum.

3. In a process of preparing thick textile fabrics impregnated with gum, introducing into the fabric during the weaving thereof looped threads forming removable cores from side to side of said fabric, treating the fabric with a very diluted latex to fix the fibres in their relative positions, withdrawing said threads from the fabric thereby leaving holes in said fabric, then immersing said fabric in a bath of concentrated latex.

4. In a process of preparing thick textile fabrics REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 963,013 Smith June 28, 1910 1,012,030 Underwood Dec. 19, 1911 1,936,974 Wallin Nov. 28, 1933 20 1,978,620 Brewster Oct. 30, 1934 

1. IN A PROCESS OF PREPARING THICK TEXTILE FABRICS INPREGNATED WITH GUM, INTRODUCING INTO THE FABRIC DURING THE WEAVING THEREOF THREADS FORMING REMOVABLE CORES FROM SIDE TO SIDE OF SAID FABRIC, WITHDRAWING SAID THREADS FROM THE FABRIC THEREBY LEAVING RECESSES IN SAID FABRIC, THEN IMPREGNATING SAID FABRIC WITH GUM AND CAUSING THE GUM TO HAVE ACCESS THROUGH SAID RECESSES TO THE INTERSTICES BETWEEN THE FIBRES OF SAID FABRIC. 